Motor-pump or compressor



1955 H. H. MCADAM MOTOR-PUMP OR COMPRESSOR 3 Sheets-Sheet 1 Filed Ailg.l, 1952 INVENTOR. HARRY H. Mc ADAM ATTORNEY June 21, 1955 H. H. MOADAM2,711,286 MOTOR-PUMP OR COMPRESSOR Filed Aug. 1, 1952 3 Sheets-Sheet 2INVENTOR. HARRY/MM ADAM WM Q June 21, 1955 H. H. M ADAM 2,711,236

MOTOR-PUMP OR COMPRESSOR Filed Aug. 1, 1952 3 Sheets-Sheet 3 INVENTOR.HARRY H. McADAM ATTORNEY ilnited States Patent @tlice 3r? angstFatentcr' June 21,

MQTOR- PUP/EP GR COMPRESSOR Harry H. McAdam, Carlos, Calih, assigrior toWetmore Hodges, doing business as Wetmore Hodges and Associates, RedwoodCity, Calif.

Application August 1, i952, erial No. 362399 15' Claims. (Cl. Ell-13?)This invention relates to an improved motor-pump or compressor of thepositive displacement type. It also relates to a sealed pump packagewhich needs only to he slipped into an electric motor stator of theproper dimensions to make a complete, leak-tight pump or compressorunit.

This invention solves many problems which have long confronted the pumpcompressor industry, particularly in relation to such applications ascompressors for domestic refrigerators, home freezers, and home airconditioners, water coolers, other refrigerated devices.

Three interrelated problems have been particularly troublesome, and thepresent invention solves them: (l) how to make small enough, lightenough, and inexpensive enough motor-compressors having the rcqu. tocapacity, (2) how to improve the dissipation of the heat which the motorcompressor build up, and (3) how to provide a pressure-tightmotor-compressor, without having to encase the whole within anall-enclosing, pressure-retaining shell. A brief discussion of thesethree important problems will aid in understanding the present inventionand its importance.

Small powerful motor-compressors have long been sought after, becausespace is always at a premium. Every cubic inch of space taken up by thepower unit subtracts from the cabinet space that can be made availableto the consumer. Moreover, large, heavy compressors have been expensiveto build, ship, and store.

Their large size was one objection to the old style of compressors,which used belts and in which the motor and the compressor wereseparately housed. Another objection to this two-unit style ofcompressor was that it required shaft seals for retaining the charge ofrefrigerant. These shaft seals were subject to leaks, squeaks andchattering noises, which could not be tolerated. Also, these seals Woreout rather rapidly and had to be replaced often.

Confronted by this problem, the reirigeration industry eliminated theshaft seals by enclosing both the motor and the compressor in a singlepressure-tight housing, which was usually an outer shell surrounding thewhole moron pump unit.

This brings us to the problem of heat-dissipation. outer shell around a[ill motor retards the passage of the heat oil into the air. The more ite motor is exposed to the air, where a coo 1 current can be passeddirectly over the hot parts, the cooler the motor can be kept. Enclosureof the motor-compressor in an outer shell terferes with and seriouslyretards the heat flow, there by tending to keep the heat in andresulting in undesirably high operating temperatures.

The above factors caused the dissipation of heat to be a more seriousproblem than is usually realized. Since electrical conductivity is afunction of the temperature of the conductor, with electrical resistanceincreasing with temperature rise, it becomes evident that a cool motorcan and will deliver more power than a hot motor. About the only thingthat could be done with a shellenclosed motor-compressor was to irrcrcmotor and the shell to compensate for through overheating, or to addcooling for the same reason. These solutions, how fiicted directly withthe problem of the keepin. cost, and wei 'ht of the compressor small.

The present invention has solved these three i A, related problems-howto keep the unit small lll light in weight, and low in cost; how todissipate the he built up inside it; and how to do these and still havea satisfactory pressure vesselby a novel structta in a pressure vesselis made from a thin imperorate e that is secured around the motor rotorbetween two end plates. This forms a compact sealed pumppacrage which beplaced inside a hollow motor stator. Al the moving parts are inside thisnovel performance has thus been solved by placing the cornpressorcompletely inside electric motor. The insolutions by the prior art wherethe compressor was placed outside the motor, often on one end of it, andin which a common drive shaft connected the compressor to the motor. Inthe present invention there is no c shaft or similar connection. Asstated above, the cat. compressor is inside the motor stator.

Another problem with prior art positive-displacemeni: motor-compressorswas that they required either an inlet valve, a discharge valve, orboth. Being moving parts, the valves were subject to many types oftrouble. The present invention has made it possible to do away withinlet and discharge valves and to replace them with simple ports. Norare any other valves needed in the remainder of its closed system.motor-pump or motor-compressor of this invention has operated success--fully in a refrigeration system that had no valve of any kind anywherein the system.

Two problems, related in their elfects and solved by the presentinvention, were the efiects in prior art compressors of torque reactionsand of eccentric rotating masses. Torque reactions due to rapidmomentary changes in load caused difilculties, for example, inpistontype compressors where large changes in load take place at the endof one compression stroke of the piston and the beginning of the nextsuction stroke. Eccentric masses caused problems in reciprocating andsingle-vane rotary pumps. Wherever there was reciprocating motion andits resultant torque reaction and Wherever eccentric masses rotated,there was considerable vibration, so that counterbalances had to beapplied to effect some reduction of this disastrous vibration. Vibrationdampeners or some other means for absorbing some of those shocks alsohad to be applied in order to reduce oscillation, noise, and wear.l-leretofore all positive displacement compressors had either eccentricmotion or reciprocating motion, or some other motion in which there wererapid changes in angular velocity or load, and all of these types ofmotion resulted in either heavy torque reaction, rotational unbalance,oscillation or vibration, all highly objectionable.

The pump of the present invention has no eccentric rotating masses andis free from torque reaction, rapid load changes and oscillation. it hasonly two rotating parts, and they rotate about their respective centersat a constant rate, so that there is no change in angular velocity. Allthe problems mentioned in the preceding paragraph, have therefore beensolved.

Another problem in motor-pumps was that the lubrication systems of theseunits would not operate it the units were placed on their sides orupside down, or in angular positions. This inadaptabillty has been onecause for other design problems involving undesirable compromisesvention should therefore be distin uished from at ted in cabinetstructure, piping systems, and the arrangement of related parts. Thepump of the present invention can operate in any attitude, because ithas a novel type of lubrication system.

In addition to solving all the problems discussed above, the presentinvention also has brought many other unusual advantages. it is aremarkably simple apparatus, having only two moving parts. it canoperate in any attitude with the same performance characteristics. Ithas none of the problems that occur where a common rotating drive shaftconnects the motor to the pump, because there is no drive shaft of anykind. The pump is driven solely by electromagnetic force; there is nomechanical driving means. Having no drive shaft in any of itsapplications, no shaft seals are needed.

An outstanding feature of the present invention is that the entire pumpunit is a sealed package that may be inserted into a stator bore andwill operate there as a pressure vessel without the need for anyexternal shell of any kind. it is a unitary device, or pump package,that may be removed from one stator and placed in another stator. Theheat from the rotor passes through the thin sleeve to the stator, andthe stator is free to dissipate its heat, because there is no externalshell around the stator. as compared with prior art pumps andcompressors.

1n the present invention all the pumping elements are mounted inside therotor of an electric motor in accordance with the invention disclosed inmy co-pending application, Serial No. 286,880, filed May 9, 1952, whichmatured into Patent No. 2,693,313 on November 2, 1954. The rotor itselfis mounted rotatably on a pair of end plates that are imperforate exceptfor the provision of intake and discharge ports, no valves beingrequired. An external tubular metal sleeve encircles the rotor and endplates and is sealed to the end plates, providing a selfcontained,sealed pump package inside the sleeve between the end plates. Thispackage, when inserted in a motor stator, becomes a complete operativepump.

The end plates provide stationary bearings that support the rotor forfree rotation. Also the engagement of the end plates in the stator boreassures uniform clearance between the stator and the rotor, a factorthat makes it possible to place the encircling sleeve between the rotorand the stator without unduly increasing the size of the air gap, asprior art attempts in this field had done.

Since the pump and compressor elements are completely contained insidethe rotor and are driven by the rotor, the only two moving pump elementsare: (1) an outer annular gear with interior teeth, which is secured toand driven by the rotor, and (2) an inner pinion gear driven by theouter gear. Both gears are perfectly symmetrical and are in naturaldynamic balance. This structure solved the eccentric rotating massproblem, because the only two elements that rotate, do so in paths whichare truly concentric to their individual centers: the pinion gearrotates about its true center, and the outer gear rotates about its owntrue center.

As in application Serial No. 286,880 (Patent No. 2,693,313), there is norotating shaft, another feature that, so far as is known, is novel inthis type of apparatus. Obviously, the absence of a rotating shafteliminates the need for connecting rods, fluid seals, outboard bearings,overhung bearings, and so on.

The novel type of positive lubrication system claimed in applicationSerial No. 286,889 (Fatent No. 2,693,313), is employed in this pump. itoperates without a sump and without the type of splash lubricationutilized in reciprocating pumps. The operation of this new lubricationsystem remains the same, whatever the attitude in which the unit isplaced.

Other objects and advantages of the invention will appear from thefollowing description of a preferred it can therefore be made relativelysmall in size,

Cal

order to comply with the requirements of 35 U. S. C. 112. It should beunderstood that the details are illustrative and are given as examplesand are not intended to narrowly limit the scope of the invention.

In the drawings:

Fig. 1 is a view in perspective of the pump package of this invention.

Fig. 2 is a view in section of a motor pump incorporating thepump-package of Fig. 1. The view is taken along the line 22 in Fig. 3.

Fig. 3 is a view in section taken along the line 33 of Fig. 2.

Fig. 4 is a view in section similar to Fig. 3, showing the rotor and itscontained parts. This view is also taken along the line 33 in Fig. 2 butlooks in the opposite direction, and the pump gears are shown rotatedthrough a relatively small angle.

Fig. 5 is a view in section of a portion of the pump package, showinghow the sleeve and nuts may be fused to the end plates.

Fig. 6 is a view in elevation of the cylindrical stationary bearingmember around which the pinion gear rotates.

Pig. 7 is a view of a modified form of end plate.

Fig. 8 is an end view of one of the nuts which secures the bolt and isitself fused to the end plates.

The pump package i shown in Fig. l is adapted to fit inside an electricmotor stator; e. g., the stator 11 shown in Figs. 2 and 3. The pumppackage it may be inserted in the bore 12 of any stator 11 and willconvert it to a complete pump.

The package fill is generally similar to that disclosed in my co-pendingapplication, Serial No. 286,880, filed May 9, 1952 (Patent 2,693,313,issued November 2, 1954), with some important differences, the principalnew feature being the tubular sleeve 15 that encircles the package andseals the entire pump package, so that no external sealing member isneeded.

The sleeve 15, which may be made of thin metal such as non-magneticstainless steel, non-magnetic Monel metal, or other non-magneticmaterial is sealed at each end to one of a pair of end plates 17, 18.Inside the sleeve 15, between the end plates 17, 18, andradially-inwardly spaced from the sleeve is a hollow rotor 20. An outergear or pump element 21 is secured to the inside of the rotor 24 Aninner gear 22 is inside the outer gear 21 and rotates around an axis C2eccentric to the axis C1 of the rotor 29 and the outer gear 21. Theinner gear pump element 22 is supported by a stationary bearing member23, which encircles the single stationary bolt 24. When the rotor 29rotates, the outer gear 21 drives the inner gear 22 and causes fluid toflow from the intake opening to the discharge opening 26.

The stator 11 Any suitably sized motor stator 11 may be used. Moststators are made up of a plurality of thin iron laminations 3t} and wirewindings 31 which pass through the slots 33.

The end plates 17, 18

allel; they provide intake and discharge ports 25, 26; they providesuitable means for connecting conduits to the ports. The end plates and13 are also recessed and drilled in certain places to provide groovesand passages that are part of the lubrication system of themotorembodiment thereof which will be described in detail in compressor.

2,71 ass In the forms of the invention shown in Figs. 1 and 2, theintake port is in one end plate 17 while the discharge port 26 is in theother end plate 18. This is not necessary, as may be seen from Fig. 7,where a single end plate has both an intake port 36 and a discharge port37. Similarly, there may be more such ports.

In their general shape, the end plates 17, 1S, and 35 are substantiallyidentical, consisting basically of a stepped disc 40 having a widerdiameter outer portion 41, and a narrow diameter inner portion 42. Theouter portion 41 may have a generally smooth outer rim 43. The innerdisc portion 42 preferably terminates in a flat wall 44, which ispreferably ground to insure that it has a perfectly plane surface. Theperiphery of the portion 42 is concentric with the rim 43 and forms abearing surface for rotatably supporting the motor rotor 25). Theproportioning, spacing, and concentricity of the two peripheries 43 and45 insure perfectly accurate alignment and spacing of the pump packageit in the stator ll, so that the rotor 26 is perfectly aligned andspaced, enabling the clearance area or air gap 46 between the rotor 25)and the stator 11 to be very small, even though the sleeve 15 is betweenthem. This assures uniform rotor-to-stator clearance and uniformrotor-to-stator parallelism. The inner edge of the bearing 45 may bechamfered at 47 to facilitate assembly of the parts and a helical oilgroove 48 may be provided around the bearing 45.

The outer periphery of the disc portion 42 may be relieved at 5%, andthere may be an annular inset recess 51 to accommodate the portions ofthe rotor 20 which extend beyond the rotor bearings 45 and to giveadequate clearance between the end plates 17, i3 and the rotor 25).

The end plates 17, 18 may also be provided with an eccentricallylocated, preferably stepped, circular opening 52 whose center C2 isradially offset with respect to the center Ci of the rim 43 and thebearing surface 45. The amount of offset depends on the diametraldifference of the ratio circles of elements 21, 22 and all other relatedfeatures of construction. The inner smaller diameter portion 53 of theopening engages the cylindrical body of the through-bolt 24, whichextends beyond the shoulder 54 into the wider diameter portion 55 of theopening 52. Blind nuts 56 may be threaded on the outer ends 57 of thebolt 24 so that the nuts 56 abut the shoulders 54 and thereby urge theend plates 17, 18 inwardly against the cylindrical bearing member 23.

The nuts 56 and the end plates 17 and 18 are shaped to providerespective thin tapering flanges or fins 58, 59 extending outwardly sothat the nuts 56 may be fused to the end plates 17, 18 by inductionbrazing, by silver soldering, or by automatic arc welding Withoutdisastrously over-heating the main body of the nuts or end plates orother adjacent parts of the pump-package.

The end plate 17, which is provided with the intake opening 25 throughwhich fluid is drawn into the pump, has, as part of the lubricationsystem, a bore 60 connecting the intake port with an annular groove 61in the opening 53. The other end plate 18, which is provided with thedischarge opening 225, also has an annular groove 62 in its opening 53,which is connected by a passageway 63 with an orifice 64 adjacent itsouter periphery 43. The effect of these lubrication passageways on theoperation of the device will be discussed later.

The end plate 35 shown in Fig. 7 is like the end plates 17, 18 exceptthat it has both an intake port 36 and a discharge port 37. The oppositeend plate may have no ports in it or it may also have an intake port ora discharge port or both. All of the intake and discharge ports 25, 26,36, 37, may be threaded or otherwise adapted to receive the ends ofsuitable conduits therein.

The motor rotor 20 The motor rotor 20 may be of the usual squirrel cageinduction design having generally-annular projecting portions 79 at eachend. Annular bearings 71 may be provided on the inner surface of thecentral rotor bore 72. The bearings 71 ride on the bearings 45 of theend plates 17, 18 and are lubricated by oil which passes along thehelical grooves 48.

The bearings 4:? and '71 serve to locate the rotor 20 in relation to thestator 11 and thereby govern the air gap or clearance 46 between theparts. They also serve to position the rotor 26 along its proper axis sothat it to tates truly about the center C1.

T he pump elements 2], 22 and the bearing 23 The outer pump element 21may be press fitted or otherwise secured to the rotor 22 in the bore 72so that it becomes essentially integral with the rotor 25 The drawingsshow a hollow gear type of a pump element 21 with a toothed innersurface 73.

The inner gear element 22 comprises a hollow cylindrical member having atoothed outer surface 74 driven by the toothed inner surface 73 of theouter element 21.

It will be obvious that the .ve pump elements 21, 22 rotate arounddifferent centers. The inner element 22 rotates around the center C2,and is made perfectly true and cylindrical so far as itself isconcerned, its bore 75 and its teeth 7 4 being perfectly concentric.Similarly, the outer periphery 76 of the outer element 21 and its teeth73 are perfectly concentric, but the outer element 21 rotates around thecenter C1 because it is fastened to the rotor 2 and rotates therewith.

Preferably the inner and the outer gear elements 22 and 21 are of theso-called Retold type, that is, they preferably have on odd number ofteeth, with the outer element 21 having two more teeth than the innerelement 22. The teeth are preferably further constructed so that thereis a sliding contact between the inner and outer elements 22, 21 whichis not broken over a corn sidcrable are as the gears rotate. In the formof pump shown in the drawings, this are will be about 240", with theopen space 77 shown in Figs. 3 and 4 being about 120. No claim is madeherein to the use of Rotoid gears per se, but only when they are incombination with the other elements shown. The Rotoid elementsthernselves are described and claimed in latent #2,547,392 issued April3, 1951, to Myron P. Hill and Francis A. Hill, 2nd.

Between the inner gear element 22 and the bolt 24, is the cylindricalstationary bearing 23 which also acts as a stop and accurately spacesapart the end plates 17, 28. The nuts 56 are tightened on the bolt untiltr e flat surfaces 44 of both end plates 17, 13 are in tight contactwith the radial faces 73 of the bearing 23, thereby placing the bearing23 under compression. The radial end faces of the gears are spaced apartfrom the end plate surfaces 4&3 enough to provide a running clearance.For this purpose they are made almost, but not quite, as long as thebearing 23. A clearance of 0.0003 inch at each end has been usedsuccessfully.

The bearing 23 is preferably cylindrical and its inner surface and outersurface 81 are concentric. The central portion 82 of the outer surface81 is relieved, and a pair of helical grooves 33 are provided around theouter bearing surfaces 34 which engage the bore 75 of the inner gearelement 22. These grooves 83 provide a path for the oil in thelubrication system which will be discussed later. Another part of thelubrication system is a radial bore 85 provided between the relievedportion 82 and an annular groove 86 provided in the interior surface 3%of the stationary bearing member 23.

The bolt 24 may be provided on its outer surface with one or more axialgrooves 87 which serve to connect the two annular grooves 61 and 62 inthe end plates 17 and 1S and also communicate with the annular groove 86in the bearing 23. Preferably the bolt 24 is provided with two suchgrooves 87 spaced diametrically apart.

As has been stated earlier, the bolt 24 and the bearing 23 arestationary, as are the end plates 17, i3 and the stator 11. The rotor 20and the outer gear element 21, being fixed together, form one rotatingelement, and the inner gear element 22. is the only other rotatingmember. The position of the bolt 24 determines the center of rotation C2of the inner gear element 22, and the positioning of the bolt 24 isdetermined by the construction of the end plates 17, 18. Thus the endplates 17, 18 must be made carefully in order to provide exactly theright eccentricity between the centers C and C2. When the end plates17', 16 are properly constructed, the motor pump is readily assembled.To prevent tampering by unskilled mechanics, the pump package 10 may bepermanently fused together by induction brazing or resistance welding,and it will continue to operate without the need for taking it apart,

Assembly of the motor pump package 10 A preferred way of assembling thepump package 10 is to first thread one blind nut 56 to one end 57 of thethrough-bolt 24 and then to pass the through-bolt 24 through the opening52 in one end plate 17. Then the hollow cylindrical bearing 23 may beplaced around the through-bolt 24, and the inner gear 22 may be placedaround the bearing 23;. The rotor 20, with the outer gear 21 secured toit, may then be placed over the inner gear 22, the motor rotor bearings71 being set to fully engage the bearing surface 4-5 on the end plate17. The other end plate 13 may then be placed over the projecting bolt24 and guided by the bolt 24 until its bearing 45 is in full engagementwith the motor rotor bearing 71. The other blind nut may then bethreaded on its bolt end 57 and drawn up with sufficient tension toachieve slight compression of the hollow cylindrical spacer bearing 23between the end plates inner faces 44,.

The sleeve 15, preferably of non-magnetic metal such as non-magneticstainless steel or 1 ionel metal, and about 0.065 to 0.010 inch thick,may then he slipped over the package unit that has been assembled thusfar. The fit with the end plates 17 and 18 is snug, with about a 3.008inch clearance between the sleeve 15 and the rotor 20. As the drawingsshow, the end plates 17 and 13 may have thin, tapered flanges or nns at59, 9t separated by a generally annular recess 91. The larger diameterfin 9G is in Contact with the sleeve 15, whereas the smaller diameterfin Si is in contact with a similar fin 58 provided on the nuts 56. Thepurpose of the thin, tapered flange or fin 9 3 is to enable thepaper-thin sleeve 15 to be cit tnferentially fused to each end plate5.7, 18 Without plate a whole or overheating aded, l h frequencyinduction heating overheating the end jacent As s a for silver solderinthe parts.

le sleeve to the end plate fin is one Another method, automatic arcwelding, co aley-ed. in either method the fused joint is completed in avery brief time period. The thin sections of metal at the apex of thefins act to retard heat flow into the relatively massive end plateduring fusion. in general. t e same process may be employed for fusingthe fins o the nuts 56 to the end plate fins 59. Here, as with thesleeve joint, fusion would occur circumferentially at he apex of theadjacent fins 58 and 59.

The pump aclsge is complete when the sleeve 15 and the two nuts 56 arefused to end plates 17, 13 by either of the above methods or by someother suitable method. The package may then be pressed into the statorit fits snugly in the stator bore 12, so that any force exerted by fluidpressure inside the pump package is actually retained by the massivewalls of the stator ll rather than by the thin sleeve wail T5. The thinwall does not substantially widen the air gap or clearance 46 betweenthe stator 11 and rotor 26. This pump package, being fused together,achieves a truly hermetic pumpmethod of joining ing mechanism that ispermanently pressure-sealed of itself. It is therefore readilyinterchangeable between any standard motor stators of proper size.

Operation and lubrication When an electric current is applied to thewindings of the stator 11, the rotor 29 will rotate on its bearings 71,35. The outer pump element 21, being rigidly mounted to the rotor 23,will then drive the inner pump element 22, and fluid will be drawn inthrough the intake opening and expelled through the discharge opening26. The reason the fluid will be moved is fully explained in the Hillpatent mentioned above and can be seen from Figs. 3 and 4 of thedrawings. The present invention is an improvement over the Hill patentsin that its Rotoid gears do not require any rotating shaft. In fact,other gears than Rotoid gears may be used, provided they make a sealwhen in mesh.

The lubrication system of pump ll) is composed of three circuits. Thefirst circuit includes the other components of a closed system, the pump10 forming only a part of this closed system. In operation, some oil isdischarged from the port 26 along with the pumped fluid. This oilcirculates alont with the pumped fluid throughout other parts of thesystem and finally reenters the pump through the intake opening 25.

The other two lubrication circuits are within the pump 1%. Due to thepositive displacement pumping action created when the gear elementsrotate, a pressure difference exists between the pump intake and thepump discharge. This pressure difference is a positive force that actsto drive oil and fluid from the higherpressure discharge portions of thepump toward the lower-pres sure intake portions. This force is utilizedand controlled for forcing predetermined quantities of oil and fluidthrough the extremely small running clearances maintained between theend faces of the rotating gear elements 21 and 22 where they nearly abutthe stationary plane surfaces 44 of the end plates 17 and 18. Since thisrunning clearance is adjustable, the quantity of oil recirculated withintne pump 10 is controllable.

Of the two recirculation lubrication circuits inside the pump 1%, one iscaused by the pressure that forces oil outwardly across both ends of theouter gear 21. Alter being forced through the running clearance at eachend, the oil enters the helical grooves 43, in both end plates 17 andi3, and lubricates the bearing surfaces 45, 71. On leaving the helicalgroove 43 of the end plate 17, the oil is driven along the clearancearea 46 between the rotor 25? and the inside of the sleeve 15, where itflows toward the other end plate i3. Here it joins with oil leaving thegroove of the end plate 18, and enters the orifice 64. The oil is forcedthrough the passage 63 in theend plate 18 and into the annular groove62. From there it is driven along the axial grooves $7 in the bolt 24 tothe annular groove 61 in the end plate 17. Then it flows through thepassage 6% in the end plate 17 into the intake port 2-5. From there theoil reenters the rotating gears 21, 22 to lubricate the meshing teethand then is forced outwardly across the gear ends, to repeat the cycle.

The third of the three lubrication circuits includes the two streams ofoil that are forced inwardly across both ends of the inner gear 22.These two streams of oil are forced under pressure through the runningclearances between each end of the inner gear and the surfaces as of theend plates 17 and 18 until they reach the bearing 23. Each stream thenenters the helical groove 83 at its end of the bearing 23 and lubricatesits bearing surfaces 84 and 75. The two streams meet at the recessedarea 32 of the bearing 23. The oil then goes through the passage 85 fromthe recess 82 into the annular groove 86 in the bore of the bearing 23.Here the oil of this third circuit joins with oil of the second circuitand flows along the axial grooves 87 to the groove 61 and through thepassage 66 to the suction or intake port 25. Here the combined streamsare joined with oil of the first lubrication circuit returning from theportions of the system outside the pump it). The three joined oilstreams then enter the rotating gears and the three cycles are repeatedindefinitely.

The three circuits are all positive-pressure systems, so thatrecirculation is assured. It will be evident that the lubrication systemin no way depends upon the attitude of the pump so that the pump may beplaced in any attitude without impairing any of its operations.

The simplicity of the pump, the novel pressure vessel, its freedom frommasses rotating off-center, its freedom from torque reaction, itspositive lubrication system, its relatively small number of parts, theelimination of rotating shafts and of valves, make the pump one that canbe made inexpensively and in a variety of sizes. its performance isremarkably fine, and a pump a fraction of the size of prior art pumpsmay have a larger capacity. Finally, in view of the facts that there isno mechanical driving connection between the pump package and thestator, and that the stainless steel sleeve 15 provides the pressurevessel, the pump package is interchangeable with other stators of theright size and will hold its charge with any such stator.

To those skilled m the art to which this invention relates, many changesin construction and widely differing embodiments and applications of theinvention will suggest themselves without departing from the spirit andscope of the invention. The disclosures and the description herein arepurely illustrative and are not intended to be in any sense limiting.

I claim:

1. A motor-pump, including in combination a hollow stator; a hollowmotor rotor within said stator; a pair of end plates in said stator ateach end of the opening therethrough, at least one of said end platesbeing ported so that said motor-pump has intake and discharge means, andat least one said end plate being slidable through said stator opening;a tubular sleeve secured to said end plates around said rotor so thatsaid rotor is rotatable inside said sleeve, said sleeve fitting snuglybut slidably against the wall of the stator; and pump means inside saidrotor and driven thereby for moving fluid between said intake anddischarge means, whereby said end plates and sleeve form a pressurevessel, containing said rotor and said pump means, that can be slid intoand out from said stator.

2. A motor-compressor including in combination a hollow stator; a hollowmotor rotor within said stator; a pair of end plates adjacent each endof said hollow stator, at least one of said end plates being ported sothat said motor-compressor has intake and discharge means, and at leastone of said end plates being slidable through said stator; a tubularmetal sleeve sealed to said end plates to provide a pressure vesselaround said rotor, said rotor being rotatable inside said sleeve, saidsleeve fitting snugly but slidably against the wall of the stator; andcompressor means inside said rotor and driven thereby for moving fluidbetween said intake and discharge means.

3. A motor-pump, including in combination a hollow stator; a hollowmotor rotor within said stator; a pair of end plates at each end of theopening through said stator, at least one of said end plates beingported so that said motor-pump has intake and discharge means, and atleast one of said end plates being slidable through said stator opening;a tubular sleeve in the air gap between said rotor and said stator andsecured to said end plates around said rotor so that said rotor isrotatable inhollow motor stator; a hollow motor rotor within saidstator; a pair of end plates at each end of said stator, at least one ofsaid end plates being ported so that said motor-compressor has intakeand discharge means, and at least one said end plate being slidablethrough said stator; a tubular sleeve of thin stainless steel secured bya pressure-tight fit to said end plates so as to enclose said rotor in apressure vessel formed thereby, said rotor being rotatable inside saidsleeve, said sleeve fitting slidably in but snugly against the wall ofthe stator; and compressor means inside said rotor and driven therebyfor moving fluid between said intake and discharge means.

5. An electric motor-pump, including in combination a hollow stator; apair of end closure plates at each end of the stator cavity, havingannular bearing surfaces projecting into said stator cavity, at leastone of said plates being ported so that said motor-pump has intake anddischarge means, and at least one said plate being slidable through saidstator cavity; a hollow motor rotor inside said stator rotatably mountedon said end plate bearing surfaces; a tubular thin metal sleeve fused tosaid end plates to provide a pressure vessel around said rotor, saidrotor being rotatable inside said sleeve, said sleeve fitting snuglyagainst but slidably in the interior wall of the stator; and a pumpingmechanism inside said rotor and driven hereby, whereby said end platesand sleeve constitute said pressure vessel and provide a pump packagecontaining said rotor and pumping mechanism, said package beinginsertable Within or withdrawable from said stator cavity.

6. An electric motor-compressor, including in combination a statorhaving a cavity; a pair of end plates at opposite ends of said cavity,said plates having coaxial inner bearing surfaces spaced radially awayfrom the walls of the stator; a hollow motor rotor inside said statorcavity between said end plates and rotatably mounted on said bearingsurfaces; a tubular imperforate metal sleeve surrounding said rotor andsaid end plates and secured at its outer ends to the outer ends of saidend plates to provide a pressure vessel around said rotor, said rotorbeing rotatable inside said sleeve, said sleeve fitting snugly againstthe wall of said stator cavity; an outer compressor element securedinside said rotor concentric therewith and driven thereby; a stationarybearing means extending between said end plates along an axis locatedparallel to the axis of said coaxial bearing surfaces; an innercompressor element rotatably mounted on said stationary bearing meansand concentric therewith and in engagement with said outer compressorelement for moving and raising a fluid from a lower to a higherpressure; and intake and discharge ports in the walls of saidmotor-compressor.

7. In an electric motor-pump, the combination of a stator having acylindrical cavity; a pair of end plates at opposite ends of saidcavity, said plates having thin annular outer rims and inner bearingsurfaces spaced radially away from and concentric with the walls of thestator cavity; a hollow motor rotor inside said stator cavity betweensaid end plates and rotatably mounted on said bearing surfaces; atubular stainless metal sleeve having a wall thickness of about 0.008inch, surrounding said end plates and said rotor and fused at its outerends to the thin rims of said end plates to provide a pressure vesselaround said rotor, said rotor being freely rotatable inside said sleeve,said sleeve fitting snugly against the wall of the stator; an outerpumping element secured inside said rotor concentric therewith anddriven thereby; a stationary bearing means extending between said endplates along an axis located parallel to the ax s of said inner bearingsurfaces; an inner pumping element to tatably mounted on said stationarybearing means and concentric therewith and in engagement with said outerpumping element for moving a fluid and raising it from a lower to ahigher pressure; and intake and discharge ports in the Walls of saidmotor-pump.

8. An electric motor-compressor, including in combination a statorhaving a cavity; a pair of end plates at opposite ends of said cavity,said plates having coaxial inner bearing surfaces spaced radially awayfrom the walls of the stator and having aligned ofl-center openingstherethrough, each said plate having an annular depression in its outerface near its outer periphery to provide thereat a thin rim portion; ahollow motor rotor inside said stator cavity between said end plates androtably mounted on said coaxial bearing surfaces; a rigid metal shellsurrounding said end plates and said rotor and bonded to said thin rimportion of each said plate, to provide a pressure vessel around saidrotor, said rotor being free to rotate inside said shell, said shellfitting snugly against the wall of said stator cavity; an outercompressor element secured inside said rotor and driven thereby; astationary cylindrical bolt-bearing means extending between said endplates and through their respective aligned off-center openings andsecured to said end 7 plates for holding them at a predeterminedspaced-apart i interval; an inner compressor element rotatably mountedon said stationary bolt-bearing means and in engagement with said outercompressor element for moving a fluid and raising it from a lower to ahigher pressure; and

intake and discharge ports in the walls of said motor-compressor.

9. A motor pump-package for an electric motor-pump, including incombination a pair of end plates each having a stepped rim with anannular bearing surface, at least one of said plates being ported, toprovide intake and discharge means; a hollow motor rotor between saidend plates rotatably mounted on said bearing surfaces; a tubularseamless sleeve secured to said end plates to form a pressure vesselaround said rotor so that said rotor is rotatable inside said sleeve;and a pumping mechanism inside said rotor and driven thereby for movinga fluid therethrough. 7

10. A motor-comprcssor-package for an electric motor-compressor,including in combination a pair of end plates each having a stepped rimwith an annular bearing surface, at least one of said plates beingported, to provide intake and discharge means; a hollow motor rotorbetween said end plates rotatably mounted on said bearing surfaces; atubular thin metal sleeve sealed to said end plates to form therewith apressure vessel around said rotor in which said rotor is freelyrotatable, whereby said compressor-package may be inserted in anysuitable stator to form a motor-compressor having a pressure vessel; anda pumping mechanism inside said rotor and driven thereby for moving afluid therethrough.

ll. A pump package for a motor-pump, including in combination a pair ofend plates, at least one of which is ported so that said motor-pump hasfluid intake and discharge means, said end plates each havingcylindrical bearing surfaces radially instepped from their rims; ahollow motor rotor rotatably mounted on said bearing surfaces; a hollowcylindrical metal sleeve around said end plates and said rotor andsealed to said end plates to form a pressure vessel in which said rotoris rotatable; an outer annular gear element secured inside said hollowrotor and connected therewith; a cylindrical bearing member heldstationary between said end plates on a different center from saidrotor; and an inner annular gear element mounted on said bearing memberand concentric therewith and driven by said outer gear element formoving fluid between said intake and discharge means.

l2. A compressor package for a motor-compressor, including incombination a pair of end plates, at least one of 'cn is ported so thatsaid motor-compressor has fluid .utake and discharge means, said endplates each having a cylindrical bearing surface radially instepped fromits rim; a hollow motor rotor rotatably mounted on said bearingsurfaces; a cylindrical shell of paper-thin rigid strong metalsurrounding said end plates and said rotor and secured pressure-tight tosaid end plates to provide a pressure vessel in which said rotor is freeto rotate; an outer annular gear element secured inside said hollowrotor and concentric therewith; a cylindrical bearing member heldstationary between said end plates on a different center from saidrotor; and an inner annular gear element mounted on said bearing memberand concentric therewith and driven by said outer gear element formoving fluid between said intake and discharge means.

13. A motor-pump-package including in combination a pair of end plateshaving a cylindrical bearing surface axially inset from its outerperiphery and having a fluid intake opening and a through-bolt openingthrough one plate and a fluid discharge opening and a through-boltopening through the other plate, said through-bolt openings being offcenter with respect to said bearing sures, each said end plate alsohaving a tapered annular session around its outer face close by itsouter iphery to provide a thin outer peripheral rim portion; a hollowmotor rotor rotatably supported on said bearing surfaces and spacedbetween said end plates; a tubular sleeve of stainless steel of theorder of about 0.005 to 0.01 inch thick fused to the outer edge of saidrim portion to provide a pressure-tight fit, whereby said end plates andsaid sleeve cooperate to form a pressure vessel around said rotor inwhich said rotor is freely rotatable; an outer pumping element rigidlysecured inside said rotor and driven by said rotor; a through-boltpassing etween said through-bolt openings and holding said pump-packagetogether; bearing means concentric with said through-bolt between saidend plates; and an inner pumping element mounted concentrically on saidbearing means and in engagement with said outer pumping element formoving fluid from said intake opening to said discharge opening.

14.A pump-package for insertion in a motor stator including incombination a pair of end plates each having a cylindrical bearingsurface axially inset from its outer periphery, said plates having afluid intake opening and a fluid discharge opening; a hollow motor rotorrotatably supported on said bearing surfaces and spaced between said endplates; a thin tubular metal imperforate sleeve secured to said endplates to provide therewith a sealed pressure vessel around said rotor,said rotor being freely rotatable inside said sleeve, so that said pumppackage may be inserted in any stator of suitable size to form aleak-tight motor pump; an outer pumping element rigidly secured insidesaid rotor and driven by said rotor; means located off center withrespect to said bearing surfaces for'holding said end plates together ata spaced interval; and an inner pumping element mounted concentricallyon said last-named means and in engagement with said outer pumpingelement for moving fluid from said intake opening to said dischargeopening.

15.A motor-pump-package including in combination a pair of end plateshaving a cylindrical bearing surface axially inset from its outerperiphery and having a fluid intake opening and a through-bolt openingthrough one plate and a fluid discharge opening and a through-boltopening through the other plate, said through-bolt openings being offcenter with respect to said bearing surfaces, each said end plate alsohaving a tapered annular depression around its outer face to provide athin outer peripheral rim portion and a thin inner peripheral rimportion around said through-bolt opening; a hollow motor rotor rotatablysupported on said bearing surfaces and spaced between said end plates; atubular sleeve of non-magnetic metal of the order of about 0.005 to 0.01inch thick fused to the outer edge of said outer rim portion to providea pressure-tight fit, whereby said end plates and said sleeve cooperateto form a pressure vessel around said rotor in which said rotor isfreely rotatable; an outer pumping element rigidly secured inside saidrotor and driven by said rotor; a throughbolt passing between saidthrough-bolt openings and holding said pump-package together; nutssecured to the outer ends of said through-bolt and fused to said innerrim portion; bearing means concentric with said through-bolt betweensaid end plates; and an inner pumping element mounted concentrically onsaid bearing means and in engagement with said outer pumping element formoving fluid from said intake opening to said discharge opening.

References Cited in the file of this patent UNITED STATES PATENTS

